1. Technical Field
The present disclosure relates to an electronic device that is powered by a battery, and relates more particularly to an electronic device that can continue operating on a secondary battery even when the main battery is removed for replacement, for example.
2. Related Art
JP 2003-101624A discloses a portable terminal that has a detector for detecting installation and removal of a battery pack (main battery), and a selector that can switch the power source required for operation of the portable terminal between the battery pack and a backup battery (secondary battery) based on output from the detector. This portable terminal is also configured to monitor the remaining power of the backup battery (the remaining battery capacity), and execute a shutdown process when the remaining power goes to or below a specific threshold.
The portable terminal disclosed in JP-A-2003-101624 enables the user to replace the battery pack while continuing to use the terminal for data input, for example, by means of the backup battery, and prevents loss of data while the battery pack is being replaced because data is saved when the remaining power in the backup battery becomes low.
However, the following problems can occur in this portable terminal while the battery pack is being replaced.
The backup battery is a battery that is provided to supply power for a short time while the battery pack is replaced, and is therefore usually a relatively small, low capacity battery in order to reduce cost, save space, and reduce weight. As a result, the backup battery will be depleted and operation of the portable terminal will be interrupted if replacing the battery pack is not completed within a specific time (such as several minutes) after the backup battery starts supplying power.
As described above, the portable terminal disclosed in JP-A-2003-101624 performs a data backup process when the remaining power of the backup battery becomes low so that data is not lost. While data loss can be prevented by this process that is predicated on the battery running out, interruption of work and use of the portable terminal due to the battery becoming depleted cannot be avoided. In order to comfortably continue using the portable terminal even while replacing the battery, some means of preventing the backup battery from running down is desirable.
If the battery capacity of the backup battery is small, the user must replace the battery pack quickly, and changing the battery pack may be rushed. Depending on the circumstances, such as during a meeting or in a dark environment, quickly replacing the battery pack may be difficult. Conversely, a high capacity backup battery can be used to increase the duration time of the backup battery so that the battery pack can be replaced without haste, but increasing the capacity of the backup battery leads to greater cost and increases the size and weight of the portable terminal.